Media captionThe US president said Sony made a mistake in not releasing its film

President Barack Obama has vowed a US response after North Korea's alleged cyber-attack on Sony Pictures.

The US leader also said the studio "made a mistake" in cancelling the Christmas release of The Interview, a satire depicting the assassination of North Korean leader Kim Jong-un.

Sony said it still planned to release the film "on a different platform".

On Friday US authorities linked North Korea to the hack, which saw sensitive studio information publicly released.

Sony said it cancelled the planned Christmas release of the film after a majority of cinemas refused to show it following anonymous threats.

"We will respond," Mr Obama told reporters on Friday, declining to offer specifics. "We will respond proportionately and in a space, time and manner that we choose."

He added: "We cannot have a society in which some dictator someplace can start imposing censorship in the United States."

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The US leader said it was important to protect both public and private cyber-systems from attack which could have significant economic and social impacts.

Mr Obama also noted he believed Sony Pictures was mistaken in failing to go ahead with the release.

"Americans cannot change their patterns of behaviour due to the possibility of a terrorist attack," he said. "That's not who we are, that's not what America is about."

Analysis: Dave Lee, BBC technology reporter

The FBI say it spotted distinct similarities between the type of malware used in the Sony Pictures attack and code used to attack South Korea last year.

Suspicious, yes, but well short of being a smoking gun. When any malware is discovered, it is shared around many experts for analysis - any attacker could simply reversion the code for their own use, like a cover version of a song.

But there's another, better clue: IP addresses - locations, essentially - known to be part of "North Korean infrastructure" formed part of the malware too.

This suggests the attack may have been controlled by people who have acted for North Korea in the past.